Generally, when hanging an object to be supported on a concrete ceiling during an installation of an air-conditioning system or the like, firstly, a fixing is secured to the concrete ceiling. A full thread bolt is screwed into this fixing, and the object to be supported is hung on the full thread bolt. In order to secure the fixing to the concrete ceiling, a hole is preliminarily formed in the fixing. A fastener is struck with a nailer, targeting this hole, to secure the fixing with the fastener.
However, it is very difficult to strike the fastener with the nailer directed to the ceiling, targeting the hole of the fixing from below.
Accordingly, there is a fixing assembly in which a metal piece having a cylindrical part is attached to a hole of a fixing, and a fastener is struck along an interior of the cylindrical part so that the fastener is easily struck into a surface of a workpiece (see, e.g., JP 52-53551 Y).
Further, there is a fixing assembly in which a synthetic resin guide member is attached to a holed portion of a fixing so that the hole can be easily targeted (see, e.g., EP 1 538 345 A1). This guide member is formed with a receiving groove around the hole to receive a circular tip portion of a nailer. By engaging the tip portion of the nailer with inner and outer groove walls of the receiving groove, it is possible to strike the fastener in a state in which the distal end portion is in a stable condition at a right position.
Further, there is a fixing assembly in which a synthetic resin resilient guide having a disc-shape is attached to a hole of a fixing (see, e.g., U.S. Pat. No. 7,093,338 B2). It is possible to strike a fastener in a state in which a cylindrical part at a tip of a nailer is fitted onto an outer side of this disc-shaped guide.
However, in all of the fixing assemblies described above, when striking a fastener, the guide member is stuck between the fixing and the fastener and becomes an obstacle, resulting in a reduced penetrating amount of the fastener.
Moreover, a surface of the fixing that faces a workpiece is flat. Therefore, in a case in which the entire surface that faces the workpiece is brought into contact with a surface of the workpiece, especially with respect to a concrete workpiece or the like that has a rough surface, the fixing is unstable and is likely to incline.